Screen changer for hammer mills



June 7, 1955 J. G. BRYANT 2,710,149

SCREEN yCHANGER FOR HAMMER MILLS Filed Feb. 27, 1955 l 4 sheets-sneu 1 INVENT OR James C1? @rg0/vf MEM ATTORNEY June 7, 1955 J. G. BRYANT 2,710,149

SCREEN CHANGER FOR HAMMER MILLS Filed Feb. 27. 1953 4 Sheets-Sheet 2 ATTORNEY 72175 l 0" infc "Z g June 7, 1955 J. G. BRYANT 2,710,149

` SCREEN CHANGER FOR HAMMER MILLS Filed Feb. 27, 195s 4 sheetssneer s l I l I INVEmoR James Gf @rg0/vf ATTORNEY June 7, 195,5 J. G. BRYANT 2,710,149

SCREEN CHANGER FoR HAMMER MILLS Filed Feb. 27, 1953 4 sheets-sheet 4 INVENTOR James G. B/"gf ATTORNEY SCREEN CHANGER FOR HAMMER MILLS .lames G. Bryant, Port Huron, Mich.

Application February 27, 1953, Serial No. 339,319

4 Claims. (Cl. 241-89) This invention relates to hammer mills and more particularly to a screen changer for such mills and it consists in the constructions, arrangements and combinations herein described and claimed.

It is a customary practice to install hammer mills in the basement of the mill, necessitating a workman going down to the hammer mill to effect a change of one size screen to another, representing a loss of time and labor. 1

It is therefore the cardinal object of'the invention to provide a mechanism which may be operated from the main lioor to effect a change in vthesize of screen positioned before the outlet openingV of the mill, as well as to lock the screen in position within the mill, lo cated in the basement.

More specifically, itis an object of the invention to provide a hammer mill wherein a plurality of screens are housed within the hammer mill, selectively movable from a remote point, into operative position before the outlet opening of the mill, and also lock the screen in operative position from said remote point.

Additional objects, advantages `and features of invention will be apparent from the following description considered in conjunction with thel accompanying drawings, wherein,

Figure 1 is a perspective view of a hammer mill installed in the basement of a mill and illustrating the relative positions of the operating means for effecting a screen change and for locking said screen in operative position before the outlet opening of the mill.

Figure 2 is a vertical section through the hammer mill.

Figure 3 is an elevation of the hammer mill illustrating the guide and housing means for the operating means to effect movement of the screens.

Figure 4 is a top plan view of the screen locking means in open position.

Figure 5 is a similar view showing the locking means in locked position when securing a screen.

Figure 6 is a plan view of the screen assembly cradle.

Figure 7 is a perspective view of a screen having an operating handle secured thereto.

Figure 8 is a fragmentary side elevation of a screen, operating strap and guide fin.

Figure 9 is a view taken on the line 9-9 of Figure 8, on a reduced scale', and

Figure l0 is a' cross section on the line 10--10 of Figure 2.

There is illustrated a well known construction of hammer mill now `in general use, indicated by the reference numeral 10. The construction and operation of the mill is well understood by those versedin the art, and only such construction of the mill as actually relate to the screen changer will be particularly described.

Attention is first invited to Figures l and 2 of the drawings wherein it will be/seen that the hammer mill 1i) is suitably mounted upon a base 10. The mill includes a Crusher 11 beneath which there is mounted a nited States Patent O ice removable door 12, in the path of which there is secured a magnet support 13. An intake plate 14 feeds material to a bottom plate 15 and bottom bar 16. Adjacent the bottom bar 16, a semi-circular screen guide 17 is bolted to respective sides of the mill at the outlet opening, the guides terminating as at 18.

A back plate 20 is bolted between respective side walls of the mill terminating above the intake plate 14 and extending approximately concentric with the rotor 21. A semi-circular cover plate 22 suitably connected between the side walls of the mill extends from the back plate 20 terminating closely adjacent the end 18 of the screen guide 17 and supports the screens while an auxiliary cover 22 mounted thereabove, arranged eccentric to the cover forming a reduced exit 22a, forms a passage-way for guiding the screens in the movement toward and away from the outlet opening of the mill.

A screen guide is arranged in spaced concentric relation to the screen guide 17, and as best seen in Figure 6, the guide 23 consists of a pair of flange members 24 held in spaced relation by means of bolts 25 and 26. The bolt 26 includes spaced collars 27 between which respective links 28 are mounted, the links being pivotally connected to a screen locking plate 29. Each of the flange members 24 are formed with` an aperture at the lower ends 30 for reception of a bolt 31 for pivotally mounting the screen guide to the sides of the mill.

As best seen in Figures 2, 4 and 5, the lock plate 29 is slidably mounted between frame members 32 at respective sides of the mill, the frame members being connected at the rear ends thereof by a spring steel bar 33 and at the front end of these frame pieces, bolts 34 are provided-extended through respective slots 35 formed in respective ends of a screen lock bar 36. A nut 37 on the bolts maintain the lockbar in slidin relation with the frame members 32.

In order that the screen lock bar may be moved into positive locking engagement with the screens employed in the mill, a linkage 38 is employed consisting of a short link 39 having one end swingably mounted upon a bolt 40 secured in the steel bar 33, the other end of the link 39 overlying a long link 41 and pivoted thereto as at 42. The long link 41 is mounted pivotally upon the lock plate 29 as at 43. A plate 44 is positioned above the long link 41 and secured to the lock plate 29 by bolts 45, the plate 44 serving to guide the movements of the link 41 when the lock plate 29 is moved into open and closed positions with respect to a screen. An elongated handle 46 is welded to the short link 39 for manually opening and closing the screen lock bar and in the closed position of the linkage (see Figure 5) the link 39 will be slightly passed dead center, and the short link 39 will engage a stop pin 47. A pair of threaded studs 48 are integrally formed upon the handle 46, equally spaced upon opposite sides of the pivot 40 of the short link. The studs 48 mount a plate 49 which is secured thereto by nuts 50.

A second operating handle 51 is required for remote control of the screen locking means, and this comprises a rod or tubing 52 secured to and extending at right angles to the plate 49 and of such length as to extend upwardly through a guide plate 53 in the main floor 54 of a building in which the hammer mill is installed.

The construction of the screens are shown in Figures 7, 8 and 9, and as seen in Figure 7, the screen 55 is of semi-spherical contour so that it may be readily moved along the upper surface of the cover plate 22 of the mill for passage between the screen guides 17 and 23, when the screen lock is in open position. The screen S5 is bolted as at 56 to a screen handle 57 which is welded to a tapered guide 58, the latter insuring proper guidance positions within the mill and as here shown, the lower l end of the tube 63 has an apertured ear 6d aligned with an ear 64 secured to the lower end of the steel strap S9, the ear 64 having a pin 64a. forming a hinge joint. lnasmuch as the straps 59 must be maintained in spaced relation so as to avoid interference, the tubes 63" and 63 include right angular connector plates 65 welded to respective straps 59, the plate connected to the tube 63 being of greater dimensions so as to properly space the strap with respect to the next adjacent strap. The

straps 59 are of a length to move the screens to the l'l operative position before the outlet opening and return the screens to inoperative positions and preferably the straps 59 will have a slight curvature which together with the inherent iiexibility thereof, the straps will move smoothly over the cover plate 22 and each other.

The tubes 63, 63 and 63" are of square formation as best seen in Figure l0 and spaced closely together so that liability of any rotative movement is avoided. An enclosure or housing 66 is employed bolted as at 67 (see Fig. 3) to the inner face of the wall 63 of the f mill and is positioned in the throat oi the mill. r{he housing 66 includes a downwardly extending guide plate 69 inclined at a suitable angle to the vertical axis of the mill and cooperates with a rod support 7d as will be described. The housing 66 is construcd from a nonmagnetic material` such as brass, so that the magnet in the mill will not be attracted.

As clearly shown in Figures 2, 3 and l0, the rod support 70 is formed from a length of angle iron 7l across `the lower end of which there is secured by welding, a

base plate '72 projecting beyond the angle iron so as to be positioned within the mill and in alignment with the enclosure 66. The base plate 72 is formed with three spaced openings 73 in each of which there is positioned a rod 74, said rods extending upwardly at the same angles as the housing 66 and guide plate l62, the rods projecting beyond the upper end of the housing and slidably support the tubes 63, 63 and 63". The rods are secured to the base plate in any approved manner, and

in the present instance, set screws 75 are employed threaded in openings formed in the base plate and impinging upon the ends of the rods.

The angle iron 7l is positioned with a flat ange '76 thereof in contacting engagement with the outside face of the wall 68 of the mill and is secured thereto by bolts 77.

As best seen in Figures 2 and lO, the guide 69 is spaced inwardly of the flange 76 so that the wall 63 of the mill may be accommodated therebetween and it will also be noted that the lower end of the guide 69 is supported by an angle bracket 7?, one leg of which. is welded to the flange 76, while the other leg is bolted to the guide 69, as at 79.

The tubes 63, 63 and 63" .re of a length to extend upwardly through a guide plate S0 mounted on the main floor 54 of the building in which the mill is installed, and each has a right angular extension 8l at their upper ends, which function as handles for manipulating the tubes. To avoid interference in elevating and lowering the tubes, the extensions Si are arranged in angular relation to each other.

The angle iron 71 is also provided with a plate S2 for closing an opening customarily formed in the side wall l68 of the mill.

fil)

sumed that screen 55 has been brought into operative position within the mill by elevating tube 63, as shown in Figures l and 2, with the screen locking mechanism in the closed position as shown in Figure 5. En order to retract the screen, an operator on the floor Sd rotates the handle 51 to move the screen locking linkage 33' to the open position as shown in Figure 4, releasing the lock bar 36 and also moving the screen guide 23 in spaced relation to the screen 55. The operator then merely exerts a downward pressure upon the tube 63 which exerts e. pull on the strap 59 which draws the screen upwardly over the other screens housed beneath the auxiliary cover 22'. Either of the other two screens may then be moved into operative position before the outlet opening in the mill by merely elevating the required tube 63 or 63 as the case may be, which will move the screen into position. The operator then rotates the handle 5l to move the linkage 38 to locked positiom in the event that it is desired to release or secure the screen at the mill, the lever 46 may be employed.

While a preferred form of the device has been shown and described, this is by Way of illustration only, and I consider as my own all such modifications in construction as fairly fall withinthe scope of the appended claims.

l claim:

l. A hammer mill having a grinding chamber provided with an outlet opening, athroat and a cover plate, an auxiliary cover plate spaced from said cover plate and forming a passage way, an inclined support fixed to the side of said hammer mill, said support having inclined spaced rods of a length to extend through said throat, a tube member slidably mounted on each rod, said tube being of a length to lextend a substantial distance above said auxiliary cover and having an operating handle, a screen member for each tube disposed in said passage way, each screen having one end of a resilient strap connected thereto, the other end of said strap being secured at a low portion of said tube, the elevation of either of said tubes moving an associated screen into position before said outlet opening, means for locking said screen in position, said means including al handle positioned at a substantial distance above said auxiliary cover for remotely actuating said locking means.

2. A hammer mill having a grinding chamber provided with an outlet opening, ya throat and a cover plate, an auxiliary cover plate spaced from said cover plate and forming a passage way, said auxiliary cover plate being eccentrically mounted with respect to the cover plate to provide a reduced exit for said screens, an inclined support fixed to the side of said hammer mill, said support having inclined spaced rods of a length to extend through said throat, a tube member slidably mounted on each rod, said tubes being of a length to extend a substantial distance above said auxiliary cover and having an operat ing handle, a screen member for each tube disposed in said passage way, each screen member having one end of a resilient strap connected thereto, the other end of said strap being secured to a low portion of said tube, the elevation of either of said tubes moving an associated screen into position before said outlet opening, means for locking said screen in position, said means including a handle positioned at a substantial distance above said auxiliary cover fOr remotely actuating said locking means.

3. The combination of a building having a basement and a oor thereabove, a hammer mill mounted in the basement, the oor above the basement having a guide plate, said hammer mill having a grinding chamber provided with an outlet opening, a throat and a cover plate, an auxiliary cover plate spaced from said cover plate and forming a passage way, an inclined support fixed to a side of the hammer mill, said support having inclined spaced rods of a length to extend through said throat and outwardly of the mill, a tube member slidably mounted on each rod, said tubes being of a length to 6 extend upwardly through the guide plate mounted in 4. The structure of claim 3, wherein the means for the floor above the mill and each tube having an Operatlocking said screen in position includes an auxiliary handle ing handle, a screen member for each tube disposed in at the mill. said passage way in superposed relation, each screen having one end of a resilient strap connected thereto, the 5 References Ced in the me 0f this Pment other end of said strap being secured to a low portion of respective tubes, the elevation of either 0f said tubes UNITED STATES PATENTS moving an associated screen into position before said 2,227,090 Hughes Dec. 3l, 1940 outlet opening, means for locking said screen in position, 2,360,892 Rench et al. Oct. 24, 1944 said means including a handle extended upwardly through 10 2,488,714 Delp Nov. 22, 1949 a guide plate in the floor above the mill. 2,669,396 Nickle Feb. 16, 1954 

